A known steering apparatus (a steering column for a motor vehicle) is disclosed in EP1583680B (which will be referred to as Reference 1). The steering apparatus including a switching device and an electric drive unit (a motor) is configured so that the switching device switches the steering column from a tilt operation to a telescopic operation and vice versa by means of a driving force of the single motor. As a result, according to the steering apparatus disclosed in Reference 1, adjustment of both the tilt operation and the telescopic operation may be realized by the single motor. In Reference 1, the driving force of the motor is outputted via a speed reducer to rotate a spindle (an external thread). In addition, the steering apparatus of Reference 1 is provided with two nuts (internal threads) consistently meshing with the spindle. The nuts are connected to a tilt link and a telescopic link, respectively. Each of the nuts is provided with a locking mechanism. Accordingly, in a case where the locking mechanism is in a locked state, the nut is restricted from rotating relative to the spindle; therefore, the nut moves in an axial direction of the spindle in accordance with the rotation of the spindle. In other words, the nut connected to the tilt link moves in the axial direction; thereby, the tilt operation of the steering column is performed. Meanwhile, the nut connected to the telescopic link moves in the axial direction; thereby, the telescopic operation of the steering column is performed. In a case where the locking mechanism is in a non-locked state, the nut idly rotates relative to the spindle; therefore, the tilt or telescopic operation of the steering column is not performed. According to the steering apparatus disclosed in Reference 1, an electromagnetic brake, an eddy-current brake, or retraction and extraction of a lock pin by use of a solenoid may serve as the locking mechanism.
As described above, the steering apparatus according to Reference 1 is provided with the single motor; however, the lock mechanisms are required for the nuts connected to the tilt link and the telescopic link, respectively. Accordingly, costs for the steering apparatus, the number of components of the steering apparatus, and the weight thereof may not be reduced. In addition, the nuts are arranged in series with each other in the axial direction. Therefore, an entire length of the steering column in the axial direction is restricted from being minimized. Consequently, assemblability of the steering apparatus to the motor vehicle may decrease.
A need thus exists for a steering apparatus for a vehicle, which is not susceptible to the drawbacks mentioned above.